(1) Field of the Invention
The present invention relates to a portable communication device having a horn antenna and a transmitter-receiver and, more particularly to a portable communication device in which the horn antenna and the transmitter-receiver are transported separately and assembled for use at the site.
(2) Description of the Related Art
In recent years, digital satellite communications systems have been widely used in various fields. For instance, they have been widely used as effective communication means by news media because the systems can rapidly send information from a news spot, to which communication line does not reach, by using a communications satellite. For such purposes, a portable communication device constructed available for portability is commonly used.
This communication device is comprised of a horn antenna and a transmitter-receiver. If the device is transported with the horn antenna and the transmitter-receiver being connected, the connecting portion, which is subjected to an excessive load of weight, may be damaged. Therefore, the horn antenna and the transmitter-receiver are transported separately and assembled for use at the site. In assembling the horn antenna and the transmitter-receiver, bolts are generally used for joining them.
However, when the horn antenna and the transmitter-receiver are joined with bolts, the thread ridges of the housing receiving the bolts may be damaged after the attachment and detachment of bolts are repeated frequently. Once the thread ridges are damaged, the joining becomes impossible. This tendency is more pronounced because the transmitter-receiver is often made of aluminum to decrease the weight.
In addition, the attachment and removal of bolts take much time and require a tool. Also, it is difficult to attach or remove the bolts by groping in the dark. These problems are especially serious when the communication device is used for news media requiring urgency.
With the portable communication device in which the horn antenna and the transmitter-receiver are connected to each other, if transmission is carried out with no horn antenna being connected, the transmitted signal is reflected by the connecting portion and returned to the transmitter because the connecting portion is open. The returned signal will destroy the transistor of the final stage amplifier in the transmitter. To prevent such a trouble, therefore, it is necessary to inform an operator of the portable communication device beforehand of the fact that the horn antenna has not been mounted.
When a communication device is used by connecting the horn antenna to the transmitter-receiver, it is difficult to ensure airtightness at the connecting portion. In particular, in the portable communication device described above, which is used under various climate conditions, external humid air and moisture are prone to enter through the connecting portion. If humid air enters the inside of the transmitter-receiver, a trouble may be caused in transmitting and receiving signals or may result in a failure. Therefore, the airtightness at the connecting portion is one of the serious problems.